Suspension 101 please?

[L_O_O_M]

I'm new to all this fabricating and custom suspension...etc so I need some help please. First off I did search, but for the life of me I can't seem to find the right information.

I am looking at buying an old Mercedes Benz w108, but I want to do custom suspension...etc. I will need to get custom springs and shocks maybe coilovers if they will work. What I would like to know is, how do you determine what shocks to use? I know you measure compressed length and uncompressed length..etc but do they come with different dampening force? and a lot of shocks or coilovers have different ways of mounting to the shock tower. Can you make adapter mounts if you have a shock you want to use but they mount differently?

[Schwartz Performance]

You can mount them however you please- they just need to be strong mounts.
As far as the shocks, you'd want to get at least single adjustable ones for unknown applications. The spring rate is more important since that's what will determine how stiff the car is overall. Bigger sway bars , new tires and new shocks are the basics in better handling. Not sure what you're looking to accomplish by doing a "custom suspension" but if you're just adding coilovers that's not much of a custom suspension.
How old is the Mercedes? If it's really outdated and you have good fabrication skills then I might suggest grafting suspension on from a different car, as their may be flaws in the factory suspension design.

I don't know enough about Mercedes to tell you anything for certain but gives ya something to think about

-Dale

[L_O_O_M]

Thanks for the feedback Schwart. It's a late 60's model Mercedes. What I meant is how can I go about looking at a suspension companies catalog and know what will work. I take it you need to know the application, unsprung weight...etc but what I would like to know is basically, will any combination of springs and shocks work as long as its with in the spec I am looking for and require? Like I see a lot of the coilovers that looks "universal", will they work on basically any car as long as it matches the vehicles weight even if you have make custom mount? I know there's a lot of factors that go into selecting the right suspension, could you maybe explain it please?

I was actually thinking of using an bmw e39 rear axle carrier as this will give me IRS as the factory rear end is swing axel.

[Schwartz Performance]

You're kind of on the right track-
T
First off, suspension is the whole system. Not just shocks, springs, sway bar, or control arms.. It's all of them together.
Yes most coilovers are universal, but some mount differently than others and are different lengths. If you were converting a Toyota Tundra into a trophy truck, ridetech coilovers would not be the best suit... But in most car applications where the suspension travel is 7" or less at the wheel then you're good. Spring rate is what's determined by your cars axle weight and if you want to race it or strictly street drive it or both. ridetech has a spring rate calculator on their site.
The BMW route would be a good choice, just have to make sure there's enough room or you'll be doing a lot more metal fab

-Dale

[HellPhish89]

wouldnt the angles and such of how the shocks are mounted affect the damping and articulation of the suspension?

[Schwartz Performance]

wouldnt the angles and such of how the shocks are mounted affect the damping and articulation of the suspension?

Yes, but more noticeable at the extremes. Obviously you wouldn't mount a shock sideways because it wouldn't have any travel. Again this is why adjustable damping and or compression on shocks is good to have.

[HellPhish89]

Yes, but more noticeable at the extremes. Obviously you wouldn't mount a shock sideways because it wouldn't have any travel. Again this is why adjustable damping and or compression on shocks is good to have.

Obviously. I ask because I always figured one would want to figure out the best position to take advantage of/manipulate/control the physical forces involved, adjustable shocks or not. I will default to your experience on the issue, just something I'm curious about.

[L_O_O_M]

You're kind of on the right track-
T
First off, suspension is the whole system. Not just shocks, springs, sway bar, or control arms.. It's all of them together.
Yes most coilovers are universal, but some mount differently than others and are different lengths. If you were converting a Toyota Tundra into a trophy truck, ridetech coilovers would not be the best suit... But in most car applications where the suspension travel is 7" or less at the wheel then you're good. Spring rate is what's determined by your cars axle weight and if you want to race it or strictly street drive it or both. ridetech has a spring rate calculator on their site.
The BMW route would be a good choice, just have to make sure there's enough room or you'll be doing a lot more metal fab

-Dale

Hi Dale, thanks for the input its really helpful. I have been doing some more research and your help is much appreciated thank you. I have been looking at shock absorber dampening rates and I am now busy reading up on how it works...etc but could please tell me if the manufactures provide you with the dampening rates so you can match them with the springs you will be using? I have been searching on sites that sell universal coilovers but don't see any dampening rates. From your experience how would you say would be the best way be to match the damping force of the shock to the spring? and I have noticed like you said that some have different ways of mounting to the car. So basically you can use any shock and spring setup as long as it falls within the requirements you need for your setup even if you have to make custom mounts for them to mount to the car? Thanks for the help.

[Schwartz Performance]

You should be more focused on how to mount the shocks and at what length, than anything right now. You'll need to weigh the car front and back to determine spring rate, as well as a few measurements. You can get shock dyno data from any of the manufacturers, they'll provide if you ask. But again it doesn't matter that much.. If it's a car, it's a car. You should be able to adjust the damping on the shock do suit your needs. The spring does most of the work, whereas the shock is just absorbing shock (compression) and releasing (rebound).
If you're really concerned, you could also get double or triple adjustables for maximum adjustability.

-Dale